1. Field of Invention
The present invention relates to pixel circuits to manage the aging of current-driven elements, such as organic EL (Electronic luminescence) elements, to electro-optical devices, and to electronic apparatuses.
2. Description of Related Art
Recently, attention has been paid to organic EL elements serving as next-generation light-emitting devices to replace known LCD (Liquid Crystal Display) elements. Since the organic EL elements are natural light elements that emit light in proportion to current, the organic EL elements have less dependence on the angle of view and require no backlight, thereby consuming low power. The organic EL elements have superior characteristics to serve as a display panel.
Methods to drive the organic EL elements, as in the LCD elements, are largely classified into an active matrix method using active elements, such as thin film transistors (hereinafter “TFTs”) and a passive matrix method not using such active elements. The former method or the active matrix method is regarded as superior because of low drive voltage and the like.
Unlike the LCD elements, the organic EL elements have no voltage-holding characteristics. Therefore, once the current flow stops, the organic EL elements cannot maintain a light-emitting state. To prevent such a problem, voltage is accumulated in each capacitor and current is allowed to flow continuously through each organic EL element by a drive transistor having a gate to which the accumulated voltage is applied. See International Publication WO98/36406 Pamphlet.